Symmetric in-wheel electric motor design

Abstract

The present invention relates to an electric in-wheel motor for a vehicle, comprising a rotor defining a rotational axis and a stator with an electric interface for connecting to an electric power source of the vehicle, a mechanical interface for connecting to a knuckle of the vehicle, and a cooling interface for connecting to a cooling system of the vehicle, wherein at least the electric interface, the mechanical interface or the cooling interface is arranged symmetrically on the stator with regard to a symmetry plane defined by the rotational axis and an upright, in particular vertical, middle axis MU of the wheel.

Description

[0001] “Symmetric in-wheel electric motor design”

[0002] TECHNICAL FIELD

[0003] The present invention relates to an electric in-wheel motor in particular for a motor vehicle.

[0004] TECHNCIAL BACKGROUND

[0005] The automotive industry is used to having specific left and right parts for vehicles as there is an inherent difference between both sides of a vehicle that cannot be avoided. More specifically, wheel mounting parts such as a knuckle cannot be interchanged. The space in the wheel is complex, many parts such as the suspension, bearings, brakes, and other parts need to be accommodated between the wheel and the chassis.

[0006] Commonly, in-wheel electric motors are therefore designed specifically for the left and right wheels. They suffer from a complex integration of interfaces requiring custom suspension and special harness routing parts and feature an asymmetric left and right motor design. Also, all known designs are concerned with the specifics of the design space when bringing the power from the inverter to the wheel. However, none addresses the liquid cooling pipeline harness.

[0007] From JP 2008001241 A, an electric in-wheel motor is known where the electric wiring follows the upper suspension arm from the inverter to the electric interface mounted eccentrically with regard to a vertical middle axis of the wheel.

[0008] In general, three- or four-wheeled vehicles are designed in a way that the suspension and the propulsion assemblies on the left-hand side and right-hand side of the vehicle are mirror- imaged, although their functions are fundamentally equal, essentially the same. This requires additional effort and extra costs for the development of such mirror-imaged products and respective production technologies. One needs to design and develop a left-hand side version and right-hand side version of the product in addition to designing similar, but in terms of means of production, different production processes which can represent a significant overhead in time and investments. At a manufacturing site, it is required to have specific tooling and settings for each motor type which raises the manufacturing costs. At the customer site, a double stocking of motors is required, and also different assembly tooling and settings are required. In the workshop double stocking of the motors is required which can present a significant increase in costs of maintenance.

[0009] At the same time, the interface design that is offered today in the case of in-wheel motors requires highly specific and non-general solutions for routing cables and cooling hoses that cause non-optimal tension, torsion and curvatures on the cables and cooling hoses which can result in reduced lifetime and required servicing. Such deformation of cables and cooling hoses can cause significant internal wear and fatigue of the cable components, such as the conductive core, insulation, EM shielding & grounding layer, etc., which can cause several types of problems, i.e., failure modes such as a loss of electrical conduction, a delamination of layers and a loss of mechanical load capacity. It also forces an asymmetric design of the knuckle which prohibits the use of common parts and therefore results in extra costs.

[0010] SUMMARY

[0011] It is an object of the present invention to overcome the above-mentioned disadvantages of the state of the art, particularly to provide an electric in-wheel motor being universally applicable on the left-hand side and right-hand side of the vehicle, wherein particularly the lifetime of the electric cables and cooling lines is increased.

[0012] This objective is solved by the subject matter of the independent claims. Advantageous embodiments are subject to the dependent claims and will be set out herein below.

[0013] A general idea of the present invention relates to an improved arrangement of the components of an electric in-wheel motor of a vehicle with respect to an interchangeability of the motor for right- and left-side wheels as well as with regard to a long-lasting guidance of electric power cables and cooling pipes required for the thermal in particular cooling management of the motor. The inventive idea of providing an interchangeable electric in-wheel motor offers significant improvements in cost reduction as motors are designed to be interchangeable, requiring a single set of tooling and settings in motor production and assembly, at the vehicle assembly site or at the servicing workshops. No double stocking is required reducing the costs of ownership born by OEM manufacturers. Placing the cooling and electrical interfaces, respectively connections, at the top or bottom provides for easy accessibility and easy air ventilation, specifically in a top-down configuration. Symmetrical mounting of the cooling and electrical interfaces and cooling inlets reduces greatly the cables and pipelines’ tension, torsion and bending upon steering, suspension travel and acceleration of the vehicle in all directions. Utilizing suspension linking components (such as the lower arm) forbracketing the cables and pipelines into a single bundle provides for a strong enough mounting structure while having the longest rotation radii regarding the vertical wheel movement. Both are advantageously exploited in this utility. Finally, a symmetric design of the machines can reduce costs on the system level by allowing symmetry in other components, but also on tools for the final assembly of powertrain components on the vehicle. The inventive idea of a symmetrical in-wheel motor particularly allows significant savings in terms of design and validation costs, industrialization (tools & layout preparation) costs, maintenance costs, production costs and logistics / supply chain management costs. There are much fewer activities needed for design and validation, as well as less costs for means of production, purchased components and materials.

[0014] According to a first aspect of the present invention, an electric in-wheel motor for a vehicle is provided. The in-wheel motor according to the present invention maybe liquid cooled, provide a torque over 300 Nm, and have an integrated friction brake. The electric in-wheel motor, in the following also called motor, in-wheel motor or electric motor, comprises a rotor defining a rotational axis and a stator with an electric interface for connecting to an electric power source of the vehicle, a mechanical interface for connecting to a knuckle of the vehicle, and a cooling interface for connecting to a cooling system of the vehicle. The rotor and the stator may be arranged in any known configuration in order to provide in-wheel power to a wheel of the vehicle in order to generate a driving force. The electric interface may comprise plug connectors for electric phase cables for powering the in-wheel motor. The electric plug connectors may be arranged in a common housing and / or be part of a connection box that may be mounted on the stator as a unit. Via the mechanical interface to the knuckle the in-wheel motor is held in place and supported by the chassis of the vehicle. Via the cooling interface the cooling management of the in-wheel motor may be realized. In this regard, fluid plugs for pipes, hoses, or the like, may be necessary in order to supply the in-wheel motor with cooling fluid, such as cooling water.

[0015] According to the first aspect of the present invention, at least the electric interface, the mechanical interface, or the cooling interface is arranged symmetrically on the stator with regard to a symmetry plane defined by the rotational axis and an upright, in particular vertical, middle axis of the wheel. Preferably, at least two or even three interfaces of the electric interface, the mechanical interface, and the cooling interface are arranged symmetrically on the stator. Due to this symmetric arrangement of the at least one interface, in particular two or three interfaces, it is possible to design the in-wheel-motor to be interchangeable with regard to a left-side use and a right-side use. By arranging the main interfaces to the vehicle in a symmetric manner with regard to the symmetry plane of the in-wheel motor, the parts to be connected to the interfaces may also be advantageously arranged on the one hand with regard to a space-saving packaging, as well as on the other hand regarding the interchangeability of the in-wheel motor. In an example embodiment of the present invention, the mechanical interface comprises two, three, or four in particular identically shaped attachment sections, each two of which are symmetrically arranged with regard to the symmetry plane. In other words, the mechanical attachment sections are located on the stator to provide an overall symmetric design with regard to the symmetry plane of the in-wheel motor. Therefore, also the knuckle to be connected to the mechanical attachment sections, that has a corresponding number of fastening sections, may be arranged symmetrically with regard to the symmetry plane and may also be identically shaped for a left-side use and a right-side use of the in-wheel motor.

[0016] In another example embodiment of the present invention, the electrical interface comprises an axial interface on a stator housing of the in-wheel motor, a connection box, and a cable subassembly, wherein particularly the connection box comprises an axial interface for attachment to the in- wheel motor stator housing, a radially inward facing connection interface for attachment of phase cables and / or radially outward facing holes for tool access to the electrical interface.

[0017] According to a further development of the present invention, the connection interface for attachment of phase cables is axially facing.

[0018] In another example embodiment of the present invention, the mechanical interface comprises two, three, or four in particular identically shaped attachment sections, two of which are arranged on a middle axis having an angle in the range of 30° to 6o°, in particular of about 450, to a middle axis being perpendicular with regard to the upright middle axis. The stator to knuckle fixation is realized by the mechanical attachment sections. One of the requirements is to provide enough space for the vehicle parts, in particular brake parts, such as drum brakes or chalet bars for disc brakes. By arranging the attachment sections with an angle with regard to the middle axis being perpendicular with the upright axis, it is possible to leave enough space for those vehicle parts to be accommodated.

[0019] According to a further development of the present invention, the electric in-wheel motor further comprises a pair of in particular identically shaped calipers being symmetrically arranged with regard to the symmetry plane and / or to a middle axis being perpendicular with regard to the upright middle axis. Being able to provide an in-wheel motor having two symmetrically arranged calipers is another important benefit for using interchangeable motors. Additionally, by providing two calipers instead of one, which is common in prior-art in-wheel motors, each of the calipers may be designed smaller in size and with regard to the requirements regarding force of braking pressure to be generated. The design of the calipers also influences the available locations for the other interfaces, in particular the mechanical attachment sections for the knuckle.

[0020] In another example embodiment of the present invention, the angled middle-axis and the middle axis oriented perpendicular to the upright middle axis span a disc sector in which the caliper is located. Therefore, it is, on the one hand, possible to accommodate the mechanical attachment sections in order to connect the in-wheel motor to the knuckle and, on the other hand, to arrange the calipers in a space-saving way which improves the guiding and attachment of electric power cables and turning pipes, hoses, et cetera.

[0021] According to another aspect of the present invention, which may be combined with the previous aspect and preferred embodiments, an electric in-wheel motor for a vehicle is provided.

[0022] The electric in-wheel motor comprises a rotor defining a rotational axis, a stator with an electric interface connected to electric power cables of the vehicle and a cooling interface connected to cooling pipes of the vehicle. The rotor and the stator may be arranged in any known configuration in order to provide in-wheel power to a wheel of the vehicle in order to generate a driving force. The electric interface may comprise plug connectors for electric phase cables for powering the in-wheel motor. The electric plug connectors may be arranged in a common housing and / or be part of a connection box that may be mounted on the stator as a unit. Via the mechanical interface to the knuckle the in-wheel motor is held in place and supported by the chassis of the vehicle. Via the cooling interface the cooling management of the in- wheel motor maybe realized. In this regard, fluid plugs for pipes, hoses, or the like, may be necessary in order to supply the in-wheel motor with cooling fluid, such as cooling water.

[0023] According to the second aspect of the present invention, the electric interface and / or the cooling interface is arranged symmetrically on the stator with regard to a symmetry plane defined by the rotational axis and an upright, in particular vertical, middle axis of the wheel, and in that the electric power cables and / or the cooling pipes are supportingly guided along the upright middle axis. By guiding the power cables and cooling pipes in a supported manner along the upright middle axis, it is possible to improve the durability and to extend the lifetime of the cables, pipes, and connections. It has been found out that supported guiding along the upright middle axis in the symmetry plane accommodates deformations better during vertical wheel movements while at the same time enabling a controlled cable- and pipe-rooting geometry with ideal steering radius. In addition, if the steering motion is considered, it has been found out that when rooting the cables and pipes along the upright middle axis the least amount of tortional stress is generated on the cables and pipes. While providing a support for the cables and pipes in the course of their travel along the upright middle axis, in particular by rigid and / or stationary suspension parts of the vehicle, deformations and stress on the cables and pipes maybe limited, preferably prevented. The routing of the cables and pipes along the upright middle axis enables that a significant length of the cable and pipe set is loaded by a torsional deflection caused by steering motions, thus decreasing torsional deformation, i.e., torsional stress on the cable and pipe set. Hence, the upright orientation of the cable pipes’ rooting accommodates the induced torsion better and enables minimum damage to the cable and pipe structure. The upright, symmetrical rooting of the cables and the pipes also minimizes the cable and pipe damage due to steering because the nature of the symmetrical load case enables minimum steering-induced torsional amplitudes. The support of the cables and pipes achieves minimal load between the cables and pipes, on the one side, and suspension parts on the other side. The cables and pipes may be supported by chassis parts of the vehicle, in particular a knuckle, a suspension arm, or another suspension part of the vehicle. Support may be realized by supporting, or guiding structures respectively, such as clamps, guiding and support channels, and other structures which help to support stability and flexibility with regard to the chassis of the vehicle.

[0024] In an example embodiment of the present invention, the electric in-wheel-motor comprises at least one fastening means, in particular at least two fastening means distributed along the upright middle axis, for guiding the electric power cables and / or the cooling pipes along the upright middle axis and for fastening the electric power cables and / or the cooling pipes to a chassis-mounted vehicle part, such as a knuckle or a suspension part of the vehicle. The chassis-mounted vehicle part maybe designed to guide as well as support the cables and pipes in the course of its travels, i.e., limit any deformation and / or relevant movement of the cables and pipes with respect to the chassis-mounted part of the vehicle.

[0025] According to a further preferred embodiment of the electric in-wheel motor, the electric inwheel motor comprises at least one securing means, in particular at least two securing means distributed along a direction away from the stator, in particular an essentially horizontal direction, for guiding the electric power cables and / or the cooling pipes in a direction away from the stator and for fastening the electric power cables and / or the cooling pipes to a suspension part of the vehicle. By using the suspension part of the vehicle which essentially extends between the wheels of the vehicle, preferably perpendicular with regard to the upright middle axis and / or in a horizontal direction, for guiding and supporting the pipes and cables, it is possible to limit deformation of the cables and pipes due to the fact that the cables and pipes are located as near as possible and closely supported by the rigid suspension parts to better accommodate the deformations during wheel movements and steering movements. In another example embodiment of the present invention, the electric power cables and / or the cooling pipes, after passing the fastening means, are bent with a minimum bending radius (Rmin) in a direction away from the stator, in particular in a direction to the at least one securing means. The cables and pipes maybe guided in the upright direction for as long as possible until they are bent in order to be connected to the electric power source of the vehicle and the cooling system of the vehicle whose components are located in the engine compartment of the vehicle. Of course, it is desirable to minimize the distance of the bending of the cables and pipes, however, it is also preferable to have a maximum bending radius in order to reduce stress on the cables and pipes.

[0026] According to a preferred further development of the present invention, the electric power cables and / or pipes are free of any fixation in the course of the bending. Thus, any deformations and / or necessary relative movements of the cables and pipes with regard to the chassis-mounted part of the vehicle, the cables and pipes may compensate in the course of the bending such deformations and relative movements in order to minimize stress and deformations in the course of the supported guiding distance of the cables. Preferably, the minimum bending radius (Rmin) is approximately in the range of 3 to 4 times the cable diameter, however depending on the technical specification of the HV cables and varying with the cross-section of the HV cables.

[0027] In another example embodiment of the present invention, the electric power cables and / or the cooling pipes are guided and / or fastened in a way to be arranged in close proximity to chassismounted vehicle parts, such as a knuckle or a suspension part of the vehicle. It has been found out that with harnessing structures located near to and closely supported by rigid suspension parts, deformation and stress may be better accommodated and compensated during vehicle and wheel movements while at the same time enabling a controlled cable rooting geometry with preferred bending curves of the cables and pipes in order to minimize the impact of stress, deformation, and torsion due to wheel and vehicle movements.

[0028] According to another example embodiment of the present invention, the electric interface together with the cooling interface and the electric power cables together with the cooling pipes are arranged with respect to each other in such a way that the electric power cables and cooling pipes are supportingly guided along the upright middle axis for a distance of at least 50%, in particular at least 60%, 70%, or at least 80% of a diameter of the stator. Maximizing the distance of supported guidance for the pipes and cables generates the maximum impact with regard to the reduction of stress, torsional deformation, and, in particular, undesired deformation of the cables and pipes, which may have negative effects on the durability and lifetime of the cables, connections and pipes. In another example embodiment of the present invention, the electric in-wheel motor further comprises a temperature sensor interface having two redundant connectors being symmetrically arranged on the stator with regard to the symmetry plane. By having redundant connectors, it is possible to either use the electric in-wheel motor for a left-side mounting of the vehicle or a right-side mounting of the vehicle. No further changes are necessary due to the fact that the temperature sensor, which is to be connected with the interface, may be interchanged or adapted respectively with regard to the left- or right-side use. With this design it is possible to connect the temperature sensor to both of the temperature interfaces without having to change the temperature sensor and without having to change the temperature sensor interface.

[0029] In another example embodiment of the present invention, the connectors are arranged on a middle axis having an angle in the range of 65° to 85°, in particular in the range of 70° to 8o°, preferably of 70°, to a middle axis being perpendicular with regard to the upright middle axis.

[0030] In another example embodiment of the inventive electric in-wheel motor, the electric in-wheel motor further comprises an angular position sensor interface being arranged on the rotational axis. This design is beneficial with regard to the overall symmetric design of the in- wheel motor and with regard to measuring quality.

[0031] According to a further aspect of the present invention, which may be combined with previous aspects and preferred embodiments of the present invention, a vehicle is provided which comprises a knuckle, a suspension part, and at least one electric in-wheel motor configured according to one of the previous aspects and / or preferred embodiments connected to the knuckle and to the suspension part. It shall be clear that the features described with regard to the inventive electric in-wheel motor analogously apply to the vehicle according to the present invention.

[0032] It is noted that a method according to the invention can be defined such that it realizes the electric in-wheel motor according to the described aspects of the invention.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The following detailed description refers to the accompanying drawings. The same reference numbers may be used in different drawings to identify the same or similar elements. In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular structures, functionality, etc. in order to provide a thorough understanding of the various aspects of the claimed invention. However, it will be apparent to those skilled in the art having the benefit of the present disclosure that the various aspects of the invention claimed may be practiced in other examples that depart from these specific details. In certain instances, descriptions of well-known devices and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. In the accompanying drawings the figures show:

[0035] Fig. 1 A schematic view of an example embodiment of an electric in-wheel motor according to the invention;

[0036] Fig. 2 Another schematic view of the in-wheel motor according to figure 1;

[0037] Fig. 3 to 6 Schematic perspective views of example embodiments of the cable and pipeline routing of an electric in-wheel motor according to the invention;

[0038] Fig. 7 A schematic diagram illustrating an example embodiment of a cable and pipe routing; and

[0039] Fig. 8, 9 Further schematic views of an example embodiment of an electric in-wheel motor according to the invention.

[0040] DETAILED DESCRIPTION

[0041] In the following detailed description of preferred embodiments of the present invention an electric in-wheel motor for a vehicle is generally indicated with the reference numeral 1.

[0042] A preferred embodiment of an interchangeable in-wheel motor design is shown in figures 1 and 2. The in-wheel motor (1) which is realized as an outer rotor motor type is mounted on a wheel (3) of a vehicle and comprises as main components a rotor (5) and a stator (7). The rotor (5) defines a rotational axis (R) of the in-wheel motor (1) and rotates with regard to the rotational axis (R) during turning of the wheel (3) and the stator (7) surrounds the rotor (5). According to the preferred embodiment of figures 1 and 2, the stator (7) comprises an electric interface (9) for connecting to an electric power-source of the vehicle, a mechanical interface (12) for connecting to a knuckle (13) of the vehicle, and a cooling interface (11) for connecting to a cooling system of the vehicle (not shown in figure 1 and 2), in particular a fluid management system, preferably for cooling the in-wheel motor components.

[0043] As can be seen in figures 1 and 2, the in-wheel motor (1) comprises an overall symmetric design with regard to a symmetry plane, defined by the rotational axis (R) and an upright middle axis (MU). Due to this symmetric design, the shown in-wheel motor (1) is interchangeably usable for the left side and for the right side of a vehicle. The mechanical interface (12) has in the preferred embodiment several attachment sections, indicated with the reference number 15, where the knuckle (13) is screwed to the stator (7). The electric interface (9) is symmetrically arranged with regard to the symmetry plane and located in an upper region, in particular an upper half, of the in-wheel motor (1) in vertical direction (V). The electric interface (9) comprises, according to the preferred embodiment, three electric connectors (17) for connecting with the electric power cables which are connected to the electric inverter of the vehicle. The electric connectors are realized for example via hollow nuts screwed to the electric interface (9). As can be seen in figure 2, the electric interface (9) and the cooling interface (11) are configured as a unit, in particular a connection box (25), housing in total five connectors (17, 19) for connecting to the electric cables on the one hand and connecting to cooling pipes on the other hand. The electric interface (9) has distinct features that allow access during assembly on the vehicle. In particular the connection box (25) comprises an attachment surface that attaches to the in-wheel motor axial surface of the stator housing (7); a cavity where electrical connections are realized, an axial or radial interface for attachment of a phase cable subassembly (17) or individual phase cables and top or bottom radial holes that allow a tool to access the main electrical connection interface of the stator windings. In an embodiment the connection box (25) also includes axial or radial holes for attachment of cooling channels (19). In one embodiment the cable connection subassembly is realized by attaching the connection box to the axial interface of the electric motor, attaching phase cables from the bottom and securing the electrical contact from the top of the connection box. This action can be realized while the in-wheel motor is already attached to the knuckle (13). In another embodiment the phase cables are attached from the axial direction and the electrical connection is secured either from the bottom or from the top.

[0044] As shown in figure 2, the two left connectors (19) are configured to be connected to the hot and cold branch pipes (H, C) of a cooling system and the three connectors (17) on the right side are configured to be connected to the three phase cables (U, W, V) for the electric supply. The inwheel motor (1) further comprises two redundant temperature sensor interfaces (21) arranged symmetrically with regard to the symmetry plane in order to be able to be occupied by a temperature sensor for a right side as well as for a left side in-wheel motor configuration.

[0045] In particular figure 2 shows another advantageous design aspect of the inventive in-wheel motor (1) with regard to the brake calipers (23). Instead of known prior art using only one bigger sized and dimensioned caliper which is arranged on one side of the upright middle axis (MU), depending on the use in a right side or left side configuration, the inventive in-wheel motor (1) comprises two symmetrically arranged brake calipers (23), thus enabling the inwheel motor (1) to be used on either the left side or the right side of the vehicle. Also, smaller calipers (23) may be used compared to the prior art calipers. Further referring to figure 2, it maybe seen that each caliper (23) is dimensioned and arranged with respect to the mechanical attachment interfaces (15) such that the caliper (23) is accommodated within a section defined by an angled middle axis having an angle 0 with regard to a horizontal middle axis (MH) being perpendicularly arranged with regard to the upright middle axis (MU). Although in figure 2, the angled middle axis is only indicated in the upper half of the in-wheel motor (1), in the lower half, the section in which the caliper (23) is accommodated can be defined by a second angled middle axis with the same but mirrored with regard to the horizontal middle axis (MH) or a different angle . The angles 0i, ip indicate the free accommodation space of the caliper (23) which shall be as big as possible due to packaging grounds. Analogously to the angle 0, the angle 01 is only indicated in the upper half of the in-wheel motor (1) but can be the same or different in the lower half of the in-wheel motor (1).

[0046] Figures 3 and 4 show further preferred embodiments of the present invention with regard to the cable and pipe routing. The in-wheel motor (1) is schematically shown mounted on a wheel (3). However, for the purpose of illustration, most of the parts of the in-wheel motor (1) have been admitted to better show the cable routing specifics. As shown before in figures 1 and 2, the connection box (25) accommodating or realizing the electric interface (9) as well as the cooling interface (11) is mounted symmetrically with regard to the symmetry plane in an upper half of the wheel (3). Also shown is the knuckle (13) connecting the stator (7) to the vehicle. Electric cables (27) and cooling pipes or houses (29) are connected to the connectors (17, 19) arranged in the connector box (25) and subsequently guided along the middle axis (MU) in a supported manner. The support is realized via fastening means (31) guiding and supporting the cables and pipes (27, 29) to the fixed structure of the knuckle (13). In the embodiment in figures 3 and 4 the fastening means (31) are arranged along the middle axis MU and spaced apart from each other and have the same distance from each other. After a significant guiding distance along the upright middle axis (MU) of at least 50% of a diameter of the stator (7), the cables and pipes are bent, indicated via the bending point (33), to further guide the cables and pipes (27, 29) in a direction away from the in-wheel motor (1) to an trunk compartment of the vehicle (not shown).

[0047] A difference between figures 3 and 4 is the orientation of the connectors (17, 19) within the connection box (25). Whereas the connectors are essentially orientated in a horizontal manner in figure 3 which leads to a first bending (35) of cables and pipes (27, 29) immediately after exiting the connector box (25), the connectors (17, 19) in figure 4 are essentially orientated in a vertical manner, thereby omitting the first bending and directly guiding the cables and pipes (27, 29) in the vertical direction along the knuckle (13). In figure 5 and 6, further example embodiments of an in-wheel motor (1) according to the present invention are shown, which basically correspond to the embodiment according to figure 4. In order to enable or achieve a significant support and guiding distance along the upright middle axis (MU), the cables and pipes (27, 29) travel upwards if the connection box (25) is located below the axis of rotation of the wheel (3) and the in-wheel motor (1) as shown in figure 5 and downwards if the connection box (25) is located above the axis of rotation of the wheel (3) and the in-wheel motor (1).

[0048] As can be seen in figures 5 and 6, the routing of the cables and pipes (27, 29) is further supported via securing means (36) which are fixed to an upper (figure 5) and / or a lower (figure 6) suspension arm (39, 41) respectively connected to the knuckle (13) and to a chassis part (37) of the vehicle. In the embodiment in figures 5 and 6 the securing means (31) are spaced apart from each other and have the same distance from each other.

[0049] The reference sign a indicates a section (43) being free of any fixation in the course of its bending between the securing means (36) and the fastening means (31). Along the rest of the cable and pipe routing, the cables and pipes (27, 29) are positioned in the vicinity of the knuckle (13) and the suspension arms (39, 41) to be fixed to these structures in several places, thus immobilizing the movements of the cables and pipes (27, 29) and transferring the gravity / acceleration loads to the mentioned structures.

[0050] In figure 7, schematic cable routing, indicated with the reference sign 45, is illustrated where the patched sections correspond to sections where the cables and pipes (27, 29) are supported by chassis-mounted vehicle parts, for example the knuckle (13) and / or the suspension arms (39? 41)- The steering angle or steering axis respectively is indicated via the reference sign cp. The section (43) being free of any fixation to rigid, chassis-mounted vehicle parts comprises a bending radius (r) and an angular extension (a). The goal when designing the cable routing (45) is to decrease the angular extension (a) and to increase the bending radius (r).

[0051] In figures 8 and 9, another embodiment of an electric in-wheel motor (1) according to the present invention is shown. In this embodiment, in addition to the lower and upper suspension arms (39, 41) a steering rod (47) is indicated, connecting the knuckle (13) to the chassis part (37)- Figure 8 shows a side view of the in-wheel motor (1) and figure 9 shows a top view of the in-wheel motor (1). Figures 8 and 9 also show the components of the in-wheel motor (1) described with reference to figure 1 and 2 in more detail, so that the symmetric design of the in-wheel motor (1) and the preferred cable routing can be seen again. The features disclosed in the above description, the figures and the claims may be significant for the realization of the invention in its different embodiments individually as in any combination.

[0052] REFERENCE SIGN LIST i electric in-wheel motor

[0053] 3 wheel

[0054] 5 rotor

[0055] 7 stator

[0056] 9 electric interface n cooling interface

[0057] 12 mechanical interface

[0058] 13 knuckle

[0059] 15 attachment section

[0060] 17 electric connector

[0061] 19 cooling connector

[0062] 21 temperature sensor interface

[0063] 23 caliper

[0064] 25 connector box

[0065] 27 electric cable

[0066] 29 cooling pipe

[0067] 31 fastening means

[0068] 33 bending

[0069] 35 bending

[0070] 36 securing means

[0071] 37 chassis part

[0072] 39 upper suspension arm

[0073] 41 lower suspension arm

[0074] 43 bending section

[0075] 45 routing of cables and pipes

[0076] 47 steering rod

[0077] R rotational axis

[0078] Mu upright middle axis

[0079] MHhorizontal middle axis 0, 01 angle n, ni angle p steering angle a bending angle r bending radius

Claims

CLAIMS1. An electric in-wheel motor (1) for a vehicle, comprising a rotor (5) defining a rotational axis and a stator (7) with an electric interface (9) for connecting to an electric power source of the vehicle, a mechanical interface (12) for connecting to a knuckle (13) of the vehicle, and a cooling interface (11) for connecting to a cooling system of the vehicle, c h a r a c t e r i z e d in that at least the electric interface, the mechanical interface (12) or the cooling interface (11) is arranged symmetrically on the stator (7) with regard to a symmetry plane defined by the rotational axis and an upright, in particular vertical, middle axis Mu of the wheel.

2. The electric in-wheel motor (1) according to claim 1, wherein the mechanical interface (12) comprises two, three or four in particular identically shaped attachment sections (15), each two of which are symmetrically arranged with regard to the symmetry plane.

3. The electric in-wheel motor (1) according to claim 1 or 2, wherein the electrical interface (11) comprises an axial interface on a stator housing of the in- wheel motor (7), a connection box (25), and a cable subassembly (17), wherein particularly the connection box comprises an axial interface for attachment to the in-wheel motor stator housing (7), a radially inward facing connection interface for attachment of phase cables and / or radially outward facing holes for tool access to the electrical interface (11).

4. The electric in-wheel motor (1) according to claim 3, wherein the connection interface for attachment of phase cables is axially facing.

5. The electric in-wheel motor (1) according to claim 1 to 4, wherein the mechanical interface (12) comprises two, three or four in particular identically shaped attachment sections (15), two of which are arranged on a middle axis having an angle in the range of 30° to 90° or up to 6o°, in particular of 450, to a middle axis being perpendicular with regard to the upright middle axis Mu.

6. The electric in-wheel motor (1) according to one of the preceding claims, further comprising a pair of in particular identically and / or mirror shaped calipers beingsymmetrically arranged with regard to the symmetry plane and / or to a middle axis being perpendicular with regard to the upright middle axis Mu.

7. The electric in-wheel motor (1) according to claim 6, wherein the angled middle axis and the middle axis oriented perpendicular to the upright middle axis Mu span a disc sector in which the caliper is located.

8. An electric in-wheel motor, in particular according to one of the preceding claims, for a vehicle, comprising a rotor (5) defining a rotational axis and a stator (7) with an electric interface (9) connected to electric power cables of the vehicle and a cooling interface (11) connected to cooling pipes of the vehicle, c h a r a c t e r i z e d in that the electric interface (9) and / or the cooling interface (11) is arranged symmetrically on the stator (7) with regard to a symmetry plane defined by the rotational axis and an upright, in particular vertical, middle axis of the wheel, and in that the electric power cables and / or the cooling pipes are supportingly guided along the upright middle axis Mu.

9. The electric in-wheel motor (1) according to claim 8, further comprising at least one fastening means, in particular at least two fastening means distributed along the upright middle axis MU, for guiding the electric power cables and / or the cooling pipes along the upright middle axis MU and for fastening the electric power cables and / or the cooling pipes to a chassis-mounted vehicle part, such as a knuckle (13) or a suspension part of the vehicle.

10. The electric in-wheel motor (1) according to claim 8 or 9, further comprising at least one securing means, in particular at least two securing means distributed along a direction away from the stator, for guiding the electric power cables and / or the cooling pipes in a direction away from the stator (7) and for fastening the electric power cables and / or the cooling pipes to a suspension part of the vehicle.

11. The electric in-wheel motor (1) according to claim 9or 10, wherein the electric power cables and / or the cooling pipes, after passing the fastening means, are bent with a minimum bending radius in a direction away from the stator, inparticular in a direction to the at least one securing means, wherein particularly the electric power cables and / or the cooling pipes are free of any fixation in the course of the bending.

12. The electric in-wheel motor (1) according to one of the claims 8 to 11, wherein the electric power cables and / or the cooling pipes are guided and / or fastened in a way to be arranged in close proximity to chassis-mounted vehicle parts, such as a knuckle (13) or a suspension part of the vehicle.

13. The electric in-wheel motor (1) according to one of the claims 8 to 12, wherein the electric interface (9) together with the cooling interface (11) and the electric power cables together with the cooling pipes are arranged with respect to each other such that the electric power cables and the cooling pipes are supportingly guided along the upright middle axis Mu for a distance of at least 50%, in particular at least 60%, 70% or at least 80%, of a diameter of the stator.

14. The electric in-wheel motor (1) according to one of the preceding claims, further comprising a temperature sensor interface having two redundant connectors being symmetrically arranged on the stator (7) with regard to the symmetry plane.

15. The electric in-wheel motor (1) according to claim 14, wherein the connectors are arranged on a middle axis having an angle in the range of 65° to 85°, in particular in the range of 70° to 8o°, preferably of 70°, to a middle axis being perpendicular with regard to the upright middle axis Mu.

16. The electric in-wheel motor (1) according to one of the preceding claims, further comprising an angular position sensor interface being arranged on the rotational axis.

17. A vehicle comprising a knuckle (13), a suspension part, and at least one electric inwheel motor (1) according to one of the preceding claims connected to the knuckle (13) and to the suspension part.

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